VB6 was written in 1998, and that installer has used the MS Java VM, which hasn't been updated or used in years. Once you get other apps install, that conflicts with the VB6 installer and you'll never get it installed.
If you have a FRESH format if your OS, you may get lucky and get the VB6 installed, but if you install other apps first, you won't get it installed. I ran into that problem before at a place I worked and installed VB6 after installing office, etc, and could never get VB6 installed, but once I changed the order of installation, then it worked.
It's better to just use VB.Net Express 2008 from Microsoft.